Multi-chamber molten metal pump

Abstract

In accordance with one aspect of the present exemplary embodiment, a molten metal pump comprising a refractory material body defining an elongated chamber is provided. The chamber is configured to receive a shaft and impeller assembly. The chamber includes an open top through which the shaft passes and a bottom inlet. The impeller is located in or adjacent the inlet. The body further defines an elongated passage adjacent to the chamber. An opening provides fluid communication between the elongated passage and the elongated chamber. The elongated passage is in fluid communication with a discharge channel configured to direct molten metal at least substantially perpendicular to an elongated axis of the elongated chamber.

The invention claimed is: 
     
       1. A molten metal pump comprising a body defining an elongated chamber, said elongated chamber configured to receive a shaft and impeller assembly, said body comprised of a refractory material, said elongated chamber including an open top through which said shaft passes and a bottom inlet, said inlet including a bearing surface receiving the impeller, said impeller being located in or adjacent said inlet, said body including an elongated passage adjacent to said chamber, an opening providing fluid communication between said elongated passage and said elongated chamber, said opening being dispersed such that a point of intersection with the elongated chamber is vertically above outlets in said impeller, and wherein said elongated passage is in fluid communication with a discharge channel configured to direct molten metal at least substantially perpendicular to an elongated axis of the elongated chamber. 
     
     
       2. The molten metal pump of  claim 1  wherein said passage is at least substantially parallel to said chamber. 
     
     
       3. The molten metal pump of  claim 1  wherein said inlet bearing surface comprises an internal face of the inlet and an impeller bearing surface comprises a radially outward surface of an impeller snout. 
     
     
       4. The molten metal pump of  claim 3  wherein said impeller includes a bottom inlet, side outlets and a top plate. 
     
     
       5. The molten metal pump of  claim 1  wherein a largest cross-section of said elongated passage is less than a largest cross-section of said elongated chamber. 
     
     
       6. The molten metal pump of  claim 5  wherein a largest cross-section of said opening is less than a smallest cross-side of said passage. 
     
     
       7. The molten metal pump of  claim 1  wherein said body is comprised of ceramic. 
     
     
       8. The molten metal pump of  claim 1  wherein each of said chamber and said passage are at least substantially cylindrical and wherein a diameter of said elongated passage is less than a diameter of said elongated chamber. 
     
     
       9. The molten metal pump of  claim 1  wherein said opening is located closer to said bottom inlet than to said open top. 
     
     
       10. The molten metal pump of  claim 1  further including elongated rods disposed within said body, said rods including mechanisms imparting a compressive force on the body. 
     
     
       11. The molten metal pump of  claim 10  wherein said elongated rods are suspended from a motor mount. 
     
     
       12. The molten metal pump of  claim 1  wherein said body is comprised of a unitary, integral, one-piece cast ceramic construction. 
     
     
       13. The molten metal pump of  claim 1  wherein said body is comprised of a unitary, integral one-piece machined graphite construction. 
     
     
       14. The molten metal pump of  claim 1  wherein a bottom wall of said discharge channel is disposed below an upper surface of the body defining said open top. 
     
     
       15. A method for transferring molten metal from a vessel, the method comprising disposing a molten metal pump in a bath of molten metal, said pump comprising a refractory material body defining an elongated chamber, said elongated chamber configured to receive a shaft and impeller assembly through an open top and position said impeller in or adjacent an inlet to said chamber, said body including an elongated passage oriented adjacent to said elongated an opening above the above the impeller providing fluid communication between said elongated passage and said elongated chamber, and wherein said elongated passage is in fluid communication with a discharge channel configured to direct molten metal at least substantially tangential to the elongated axis of the elongated chamber, and wherein rotation of said impeller elevates molten metal within said elongated chamber to a level above the opening and said elongated passage such that molten metal is selectively discharged from said pump via said discharge channel. 
     
     
       16. The method of  claim 15  wherein the molten metal rises substantially in equilibrium within the elongated chamber and the elongated passage when an adequate speed of rotation of the impeller is initiated. 
     
     
       17. A molten metal pump comprising a body defining an elongated chamber, said chamber configured to receive a shaft and impeller assembly, said body comprised of a refractory material, said chamber including an open top through which said shaft passes and a bottom inlet, said impeller being located in or adjacent said inlet, and wherein said chamber is in fluid communication with a discharge channel located at a top end of said body and configured to direct molten metal at least substantially perpendicular to an elongated axis of the elongated chamber, and wherein said body includes a plurality of rods having a first anchor end disposed in said body and a second attachment end secured to a pump support assembly, said rods further receiving a compressible element configured for establishing a compressive force on said body, said compressible element comprising a spring and nut assembly.